This invention relates to seal structures for loading docks whereat a cargo body of a truck or trailer is backed against the doorway at the dock, and especially to a resilient seal structure surrounding the top and sides of the doorway and engageable with the rear end of the cargo body to provide a seal against rain and cold during loading and unloading operations.
More particularly, the invention relates to a loading dock structure whereat the end of the cargo body is horizontally spaced away from the top and sides of the door opening due, for example, to the installation of a vertically adjustable platform interposed between the floor of the dock and the floor of the truck. This arrangement requires that the seal structure be spaced away from the doorway to sealingly engage the end of the cargo body.
In prior art, loading dock door seals such as the seal arrangement shown in U.S. Pat. No. 4,015,380 dated Apr. 5, 1977, the floor of the loading dock extends only through the door itself and not significantly beyond. The seal structure is located on the exterior of the door frame facing outward. When the cargo body is backed against the seal, the seal may be compressed somewhat but the floor of the truck is closely spaced to the floor of the dock itself. Ramps may, of course, be used for loading and unloading cargo to and from the cargo body.
This arrangement, however, is not satisfactory in the case of newer cargo body designs wherein a vertically adjustable platform is often provided at the end of the cargo body to facilitate the loading and unloading operation. These platforms are often operated hydraulically and are interposed between the dock itself and the floor of the cargo body.
It will be apparent that with this configuration, it is not possible to move the truck cargo body far enough back to engage a prior art loading dock door seal of the type described, due to the interference caused by the adjustable platform.
The loading dock door seal arrangement of the present design provides a means for extending the seal structure of the type described in U.S. Pat. No. 4,015,380 sufficiently outward away from the doorway to permit engagement with the cargo body while providing sufficient space to accommodate an adjustable platform. At the same time, the means for extending the seal structure provides its own means for enclosing the space between the seal itself and the doorway.